Hydraulically operated tier-lift mechanism for industrial trucks



Jan. 19, 1954 J, ABBE 2,666,501

HYDRAULICALLY OPERATED TIER-LIFT MECHANISM. FOR INDUSTRIAL TRUCKS Filed Dec. 20. 1949 6 Sheets-Sheet 1 I 42..) 40 5 42 E f INVENTOR. Fi7.4 gamma .1. A886 jdmi A TTORNEYS 6 Sheets-Sheet 2 mzm/ a 4 4 4 8 m A 6 s 5 5 F T V y 5 U a 6 F m J m w 2 Y |1| 1| D 0 3 o o o o o o o o o o o o o o o o o o o o o o o o o m w m m 7 m --m.---- m m 4 y 686 rl Ill |I| I: n NJ I o 4 6 3 5 2 M Jan. 19, 1 E. J. ABBE HYDRAULICALLY OPERATED TIER-LIFT MECHANISM FOR INDUSTRIAL TRUCKS Filed Dec. 20, 1949 E. J. ABBE HYDRAULICALLY OPERATED TIER-LIFT Jan. 19, 1954 MECHANISM FOR INDUSTRIAL TRUCKS 6 Sheets-Sheet 4 ///fl/A/AM \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\S INVENTOR. fan A190 A585 )2 ja/ua 61%;

Filed Dec. 20, 1949 6 Sheets-Sheet 5 J. ABBE HYDRAULICALLY OPERATED TIER-LIFT MECHANISM FOR INDUSTRIAL. TRUCKS Jan. 19, 1954 Filed Dec. 20, 1949 INVEN TOR. 6010490 J. A885 Jan. 19, 1954 E. J. ABBE HYDRAULICALLY OPERATED TIER-LIFT MECHANISM FOR INDUSTRIAL TRUCKS 6 Sheets-Sheet 6 Filed Dec. 20, 1949 JNVENTOR.

EDWAED J. 48155 Patented Jan. 19, 1954 HYDRAULICALLY OPERATED TIER-LIFT MECHANISM FOR INDUSTRIAL TRUCKS Edward J. Abbe, Cleveland Heights, Ohio, as-

signor to The Elwell-Parker Electric Company, Cleveland, Ohio, a corporation of Ohio Application December 20, 1949, Serial No. 134,098

vating reach without increasing the number of telescoping elements of the frame while confining the telescoped door or overhead clearance thereof to standard requirements.

A further object is to provide one form of the invention wherein a hydraulic ram arrangement for the above stated purposes and uses will involve the use of only a minimum of over-all lengths of flexible elements, such as cables or chains.

A still further object ofthe present invention is to provide a telescopic frame and compound hydraulic ram mechanism wherein the load elevating carriage traversing the frame members is operated by the ram mechanism in such manner that the carriage will be elevated relative to both frame members during the first stage of operation of the ram mechanism and, thereafter the elevatable frame member and the carriage will be elevated in unison in either a, direct or a two to one ratio of load and ram movement, respectively.

Other objects and advantages of the invention will be apparent from the following detailed descript'ion of preferred forms of embodiment of vthe invention, reference being made to the accompanying drawings wherein- Figs. 1 and'2 are side elevational views of a tier lift industrial truck incorporating the features of my invention;

Fig.3 is a top plan view of the tier lift mechanism shown in Figs. 1 and 2;

Fig. 4 is a cross-sectional view of the tier lift mechanism taken horizontally substantially along the line 44 of Fig. 5; a

Fig. 5 is an enlarged front or loading end view of the tier lift mechanism and supporting truck wheels with the loading platform or forks in down position;

Fig. 6 is a cross-sectional elevation of the tiering mechanism as viewed in. cross-section indicated by the line 6-6 in Fig. 5;

Fig. 7 is an enlarged elevational view of the tiering mechanism partly in ram center line 2 Claims. (01. 187-9) .2 cross-section and with the mechanism in maximum vertically extended position;

Figs. 8 and 9 are side elevational cross-sections taken in a ram center line plane extending longitudinally of the truck;

Fig. 10 is a cross-sectional elevation taken through the center of the ram mechanism on a plane extending transversely of the truck and showing a modification of the invention;

Fig. 11 is a cross-sectional elevation of the modification shown in Fig. 10 and taken substantially along the line l&l ll of that figure; and

Figs. 12 and 13 are cross-sectional elevations taken longitudinally of the truck and showing two operating positions of the ram mechanism.

My invention contemplates the utilization of hydraulically applied power to the load elevating'mechanism of a tier lift truck in such manner as to obtain a load tiering lift of more than ten feet with a single telescoping mast or upright structure which, when in lowered approximate floor loading position, will permit the truck to pass through relatively low doors. Hydraulically operated tier lift trucks having a door clearance design of the telescopic mast structure have been limited in lifting capacity unless more than one elevatable sliding frame was used. When more than one ele'vatable frame is used the load overhangs and the weight of the elevating mechanism and the power consumed are increased. In storage battery powered trucks the increase in power consumption is a serious problem. However, the higher the elevating capacity of the v mechanism the more overhead Warehouse space can he used.

I have found that it is possible to obtain the desired extraordinary lift or load elevating capacity while retaining the advantages of hydraulic actuation by changing the accepted sequence'of operation of the main elements of the tiering mechanism wherein the load carriage was raised in a two to one ratio only in a limited amount before the telescoping frame elevation commenced.

In the present invention the elevatable mast frame is elevated directly by the hydraulic ram mechanism only after the carriage has been elevated the complete length of the elevatable mast frame. The load carriage thereafter is carried upwardly in unison motion with the upward movement of the movable mast element. The foregoing movements in the sequence stated can be accomplished by the use of a duplex or compound ram mechanism in which a mechanism, which I call a secondary ram, effects the direct elevation of the movable mast member and a sec ond ram mechanism, which I call a primary ram, effects the upward movement of the load carriage on the extensible mast member before this mast member has any upward movement. The two ram mechanisms are in a compound arrangement of concentricity whereby both the pistons and one of the cylinders also serve as hydraulic ducts. The hook-up is such that one ram mechanism slides upon the cylinder of the other ram mechanism and so that it will remain immovable relative to the load carriage during the elevation of the movable mast member by the secondary ram.

Referring to the drawings, in Figs. 1 and 2 I show a side elevation of the tiering mechanism, the general telescopic mast structure or uprights of which may be of a well known form. The two main relatively movable elements thereof extend to the desired height and the height is limited only by the door or overhead clearance environment of the truck use. The mast comprises outer spaced-apart channel members 29 with channels facing inwardly and connected to the top by a cross-frame member 2| of the shape shown in Figure 3. The channel members 29 are crossconnected at the bottom by a suitable cross structure 25 which also serves as a thrust bed or support for a hydraulic ram mechanism as will be described. I choose to designate the lower section of the mast including the channels 20 as a fixed frame or immovable mast element but the same may be pivotally connected for tilting of the entire tiering mechanism or it may be rigidly connected as desired to the end 28 of the chassis structure of the truck immediately forwardly of the load bearing truck wheels 29; This vertically immovable channel structure is arranged to overhang the truck end as shown in Fig. 1.

The upper section of the mast, that is, the movable mast element or movable frame structure comprises inner channel members 30 having rollers 3| mounted thereon to ride the flanges of the outer channel members 20. The inner channel members are-disposed to have the channels thereof face inwardly and are connected by a topstructure 32 and a lower cross structure 34 which clear the top cross member 2| of the fixed mast frame when the inner mast frame is elevated. This arrangement permits the inner frame structure to be slid into or out of the outer frame by insertion thereof. at the top of the outer frame structure.

The load elevating carriage is shown as comprised of fork members 40 mounted on a carriage 4| having rollers 42 which ride the flanges of the inner channel members 30. A load platform may be used instead of the forks. The

carriage structure is such as to permit the carriage to traverse the height of the inner channels 30 less the distance between the upper pair and the lowerg pair of carriage rollers 42. The inner channels or inner frame may traverse the height of the outer fixed channels less the distance between the upper pair and the lower pair of channel rollers 3|. It will be noted that this distance is shown as being considerably greater than the vertical roller spacing distance of the carriage rollers 42 for stabilizing purposes.

The compound ram mechanism is centrally disposed within the described telescopic mast structure and comprises a secondary hollow cylindrical piston member 50 attached to the bottom cross structure 25 of the outer fixed frame structure. The cylinder 5|! extends almost the height of the collapsed height of the mast structure and serves as a slide for the primary ram mechanism. The bottom mounting of the cylindrical piston member 5| is such as to permit aligning movements thereby to follow the elevatable mast and to afford pressure fluid connection through conduit 5| to a source of hydraulic power (not shown) located on the truck. Slidable upon the secondary hollow piston 55 is a cylinder 55 having the upper end thereof closed by a plug I56 with a reduced threaded extension |5'| passing through an opening in the top cross structure 32 of the inner frame. A nut I58 serves to hold the upper end abuttedly fixed to the top cross structure. If desired an air lock release passageway sealed by small plug 59 may be provided in the plug I56. The cylinder-piston unit 5055 has the function of completely extending the inner frame relative to the outer frame.

The inner end of piston 5|! is provided with suitable fluid retaining packing 52 slidable on the internal surface of cylinder 55 and the cylindrical member 55 is provided at the lower end thereof with a packing gland 5G and nut 51. This gland slidably seals the bottom of cylinders 55 and B5 on the outer surface of the inner cylindrical piston 50 and the retaining structure 58 for the gland and nut may comprise the bo tom wall of an outside cylinder '65 of a primary ram mechanism. Thus the cylinder 55 is in fixed or rigid relation to this outer cylinder 55.

As hereinbefore stated, the primary ram mechanism serves the purpose of effecting elevation of the load carriage relative to the mast frame before the mast frame has been moved or extended by the secondary ram comprising the cylinder and piston members 50-55. Ac cordingly there is disposed within the outside cylinder 55 a primary piston 10, upon the head 150i which is fixed a sprocket bracket 15 having a pair of sprockets 11 mounted thereon to span the cylinder mechanisms. The piston head 15 is provided with a gland T8 for slidably sealing the upper end of the piston ill on the outer surface of the secondary cylinder 55. The outside cylinder 65 is provided, at its upper end with a packing gland i9 and nut which slidably seals the outside cylinder relative to the outer surface of the primary piston 10.

The inner hollow piston member 50 is provided with a hydraulic connection to the source of pressure through passageway 53 formed in bottom mounting member 54 and this bottom member is pivotally connected to lugs .2 Ed on the fixed frame bottom structure by a pivot pin 26. If desired, a second pivot pin or studs disposed 90 to pin 26 can beused to provide a universal mounting. The secondary cylindrical piston 50 thus serves as a conduit and it is provided with lateral ports 82 and cylinder 55 has laterally extending ports 83 which establish fluid communication with the primary piston and cylinder. The locations of these ports are such that hydraulic pressure can be applied simultaneously to the pistons of both the primary and secondary ram units at any and all elevated positions of the inner frame and of the carriage.

The load carriage is connected to the primary ram mechanism by flexible means in the form of link chain reaches 85 which are reeved over the sprockets with one end of each chain connected at 84 to the carriage and the other end to ananchoring bracket 86 welded or otherwise secured to the external surface of the primary cylinder member 65.

Suitable stops may be provided either on the mast elements or within the ram units for stopping the upward movement of the extendable mast member relative to the fixed mast member and the carriage relative to the extended mast member. In Figs. 8 and 9 I show a ring 88 having oil flutes, which is held against an internal shoulder Within the primary piston 65 by an expanded ring 89 seated in an internal groove and which serves as a spacer on the upward movement of the primary piston. Stop ring 90 welded or fixed to the lower end of piston I encounters ring 92 held in place near the top of the primary cylinder 65 in the manner of holding fluted ring 88. Also, a stop ring 9| can be mounted on the cylindrical piston 50 to abut the inner upper end 58a of the bottom wall member 58 to limit the secondary movement. 7

In operation the hydraulic line -I leading to the cylinder 50 is manually controlled to connect the ram mechanisms to a source of fluid pressure and to release the fluid to a reservoir. When the ram mechanisms are subjected to hydraulic pressure this pressure is exerted upon plug end I 56 and upon the plug 'Ifi'simultaneously by reason of the port arrangement. The primary piston I0 is raised first to raise the carriage on the elevatable channel frame in one to two ratio i during which action this frame remains in the down position. The secondary cylinder 55 and the movable mast frame then are lifted with the load elevated relative to this mast frame without any relative movement taking place between the upwards in a sliding manner on the fixed cylindrical piston 50, since primary cylinder 65 is fixed relative to the secondary cylinder 55. Any load lifts not exceeding the carriage travel on the extensible mast frame are efiected by the primary ram without any operation of the secondary ram taking place. This sequence of operation is caused by the fact that the primary piston I0 has a substantiallygreater effective" hydraulic pressure area than the secondary cylinder 55. Stated another way, the primary ram mechanism operates, or is responsive to, a lower line pressure than the secondary ram mechanism. In the design shown the operator may regulate the line pressure to about 750 pounds per square inch and the primary ram will raise the carriage and load. Increasing the line pressure to about 900 pounds will cause the secondary ram to operate. By controlling the release of line pressure the mast will be lowered first.

In the following description of operation it will be noted that since the sprocket chain ends are anchored to the arrested outer cylinder 65 the load carriage is elevated by the chains at twice the rate of upward movement of the sprockets and primary piston I0. Release of line pressure permits the respective mechanisms to lower by gravitational influence and this lowering movement can be regulated if desired by regulating the rate of outward flow of the hydraulic fluid. The particular mechanism illustrated in Figs. 1

to 9, inclusive, has been used in a tier lift truck having a load elevating range of 128 inches with a line pressure of about up to 950 pounds per square inch. The primary ram produced a carriage elevation of 64 inches and the secondary ram had an efiective movement of 64 inches. If desired a latching mechanism tying the elevatable mast to the fixed mast may be disposed near the top of the mast structure to hold the elevatable mast down until the carriage has risen to the top of the inner mast, at which place the carriage will release the mast.

In the modification as shown in Figs. 10 to 13, inclusive, like numerals have been applied to designate like parts of the mechanism shown in Figs. 1 to 9, inclusive, and with considerable detail omitted. The mechanism is substantially the same in its elevating effect, but multiple reeving has been used to shorten the primary piston and cylinder elements. In this form the secondary ram mechanism is not connected directly to the top cross structure 32 of the extensible element of the mast. The sprocket bracket 98 is mounted, however, upon the top of one of the cylindrical pistons. The connection between the ram mechanism and the extension mast member comprises sprockets I00 mounted on a bracket IOI attached to a lowerregion of the extensible frame. The

chains have ends thereof attached to the carriage at I02 and extend upwardly and pass over, two pairs of small sprockets I03 and I04 mounted on the top of the extensible frame member and then extend downwardly and pass under the sprockets I00, then up and over the piston sprockets TI. The opposite ends of the chains are anchored to the bottom cross structure of the fixed mast element by the rods I05. In this arrangement the relative movement between the extensible upright or mast element and the carriage takes place throughout the primary elevating action of the compound hydraulic ram mechanism and while the movable mast remains in down position as in the first form shown in Figs. 1 to 9.

As shown in Fig. 10 an inner fixed cylinder I I0 is mounted on the bottom structure of the fixedframe 20. This fixed cylinder is hollow and the-upper end is open. This fixed cylinder H0 .serves as a slidemount-ing for a short cylindrical member III and serves the same purpose as plunger of the first form. The short cylinder member H I at its bottom also comprises the bottom structure of an outside cylinder I I4. A packing gland H3 and nut H5 seals the bottom of cylinder III. Within the outer cylinder H4 is a cylindrical piston I20 which corresponds to the primary piston 50 of the ram mechanism shown in Figs. 1 to 9, inclusive. The primary piston I20 has the sprocket bracket 98 mounted on the top thereof. The outer cylinder H4 has the top thereof closely slide fitted on the primary piston I20, but a packing gland such as gland 19-80 of Figs. 8 and 9 would be provided at the top of cylinder H4. Fluted guiding lands Hd'a are formed at the top of fixed cylinder H0 to slidably contact the inside of the primary cylinder I20 and these lands, together with fluted lands I20a, located near the bottom of the primary piston I20 to contact the inside of outer cylinder H4, serve to maintain alignment of the primary piston I20 with the outer and inner cylinders. The lands can also serve as stops if desired.

In operation, as stated, both the carriage and. movable mast have relative movement to each. other and the movable mast has no relative; movement to the fixed mast during the primary 7 stages of operation of the carriage and the outer primary cylinder stays down until the piston I20 has been raised to the position shown in Fig. 12.

Until the time the carriage reaches the top of the movable mast, the movable mast remains down, but when the carriage reaches the top thereof a pair of carriage side plates Ma encounter the obstruction of the movable mast top cross structure whereupon the movable mast and carriage move upwardly in unison. The completion of this first stage is shown in Fig. 12 and if desired a latching mechanism (not shown) can be used between the fixed mast and movable mast to hold the latter down until unlatched by the up positioning of the carriage.

In Fig. 13 the movable mast 30 is shown in upwardly extended position and with the carriage 4| in upwardly extended position relative to the movable mast 30. The carriage has been i maintained in that position by the ram mechanism through the elevating period of the mast 30. The ram cylinder H4 has been moved upwardly by the bottom lands l20a encountering the upper gland structure of the cylinder H4. It will be noted that I have provided a port I201) which assures establishment of fluid communication on both sides of the cylindrical wall of the piston I20 when the lower part of the piston is in telescopic relation to the slide cylinder III.

In both forms of the invention the carriage is maintained at the top of the movable mast by hydraulic pressure as the ram mechanism thereafter raises the movable mast. In the second form there is a two to one ratio movement of the mast 30 relative to the ram sprockets H.

In the compound hydraulic mechanism shown in the first embodiment an unusually long secondary cylinder 55 and cooperating fixed cylinder 50 are used, thus requiring only short chain reaches. In the modification the secondary cylinder HI can be shortened considerably since it is not attached directly to the movable mast or frame but comparatively long chain reaches are required to provide the lifting sprockets 100.. While no ram aligning support has been shown in the modification it will be understood that such a support can be used if means is provided to limit the swaying movements of the ram mechanism.

I claim:

1. In a lift truck having telescopic uprights operatively supporting a load tiering carriage which is actuated by one of a plurality of compound piston-cylinder rams concentrically arranged one within the other, said rams consisting of a hollow piston-cylinder unit reacting on the telescopic uprights to extend the same vertically and a hollow piston-cylinder unit surrounding the first named unit and connected to the carriage by flexible means to elevate the carriage relative to the telescopecl uprights: movement limiting means disposed between the respective pistons and. cylinders comprising an expanded ring supported in a groove in the internal face of the cylinder of the carriage operating ram serving as a stop for a bottom flange ring on the carriage operating piston, and a spacer ring carried on a second expanded ring supported in a groove in the internal face of the carriage operating piston and disposed between the carriage operating piston and the upright operating cylinder.

2. A lift truck comprising a chassis, a telescopic mast mounted on the chassis comprising a lower section supported by the chassis and an upper section telescoping with the lower section, a load elevating carriage movable along the upper section; a compound ram mechanism comprising two ram units concentrically arranged relative to each other, one unit comprising a cylinder. coupled to the upper section of the mast and a plunger coupled to the lower section, the other unit surrounding the piston-cylinder elements of the first unit and comprising a cylinder fixed at its bottom to the upper mast section cylinder and open at its top and. a carriage ram plunger extending downwardly through the top open end of the carriageram cylinder, adjustable packing means supported by the upper end of the carriage ram cylinder, a second adjustable packing means secured to the upper end of the carriage ram plunger and sealing the carriage ram plunger relative to the upper mast section cylinder, a sprocketsupporting ring mounted upon said second packing means, said second packing means having a gland tightening thimble extending upwardly therethrough but spaced from the sprocket supporting ring, and a spacer ring mounted internally of the bottom portion of the carriage ram plunger for stabilizing the vertical movement of the carriage ram plunger relative to said second packing means. 7

EDWARD J. ABBE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,505,009 Schroeder Apr. 25, 1950 2,595,959 Lawless May 6, 1952 

